Compressor for Pressurized Fluid Output

ABSTRACT

A compressor moves a fluid from an inlet to an outlet and provides a pressure differential there between due to respective pistons moving in and out of a plurality of piston chambers via a piston rod. A rotating shaft extends through a grooved end plate, and the rotating shaft is connected to either the grooved end plate or the piston rod. The grooved end plate defines an off center or eccentric groove. A bearing extends from the piston rod and fits within the groove such that when the rotational motion of the shaft rotates either the piston rod or the grooved end plate, the piston rod slides back and forth relative to the rotating shaft. Each position of the bearing within the groove determines a corresponding position of the piston rod relative to the rotating shaft. Each pair of pistons may extend from a single, continuous piston rod.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and incorporates entirely byreference herein U.S. Provisional Patent Application Ser. No. 61/585,828filed on Jan. 12, 2012.

FIELD OF THE INVENTION

The invention relates to the field of gas compressors that have an inputfor a gas and an output for the gas, wherein the gas has an adjustedpressure at the output due to the operation of pistons within thecompressor.

BACKGROUND

Compressors for air, gas, and fluid movement are in constant need forthe medical, automotive and beverage industries, just to name a few.Piston pumps are well known in the area of compressors. Piston pumpstraditionally include a rotating shaft having a concentric attached witha piston moving up and down (i.e., reciprocating). One version of apiston pump is a wobble piston pump (FIG. 1) and has the piston rod (20)attached to the piston (18) on one end and an eccentric bearing assembly(25) on the opposite end. As a rotating shaft (23) rotates about thebearing assembly (25), piston rod (20) changes positions (as shown inthe dotted lines of FIG. 1) and causes the piston (18) to shift up anddown from one side to the other (i.e., the piston “wobbles”) The piston(18) rocks up an down from left to right and uses a Teflon seal or cup(14) to apply pressure to opposite sides (16A, 16B) of a chamber (17)such that one side of the chamber creates a vacuum (e.g., an inlet (10))and one side of the chamber creates positively pressurized displacement(e.g., outlet (12)). These pumps have limited up and down travel anddisplacement and are good for pressure adjustment, but for volume theyhave a short compression stroke and displacement size per revolution.They are not efficient in total volume of air/gas movement due tolimited piston travel and displacement. More compressor heads may beadded but more space and weight is required. These compressors arenoisy, have a lot of vibration, and are heavy due to the metalconcentric needed as part of the assembly. Wobble pistons offer limitedair volume when considering size and weight. The Teflon piston isreliable; however, per revolution volume is low and efficiency is poorwhen total volume of air/gas moved is considered vs. power consumed.They also have a pulsing flow, not a smooth output flow. Rocking backand forth, they tend to pull air from around the end of the pistoninstead of through the intake, thus there is a contamination problem.

Another kind of prior art compressor includes a rotary vane pump (FIG.2). As shown by the image of a Gast® compressor in FIG. 2, thecompressor includes a rotating shaft in an off center, or “eccentric”position with respect to the interior of the compressor. Piston rods(40) connect sliding vanes (42) to chambers (43), and the eccentricposition of the rotary shaft provides different travel lengths for thevanes to slide inwardly and outwardly at positions about an innercircumference (45) of the compressor. As the space within the compressoris available to allow the vanes to thrust outward (e.g., vane (42B)), avacuum is created in the piston chamber (43) and as the vanes are pushedback in (i.e., vane position 42(D)), fluid or air or gases collected inthe piston chamber (43) are compressed within the respective chamber(43)). The compressed gases or fluids within a chamber (42) are allowedto exit at an outlet (31) with a higher pressure than that found at theinlet (30) of the compressor. Rotary vane pumps often utilize carbonvanes with compressor bodies made of steel. These materials have lowthermal expansion and are required because of very close tolerance forspacing. These compressors offer high volumes of air per revolution dueto the opportunity for using multiple vanes. They are not for highpressure. These rotary vane compressors are very heavy and have a carbondust problem and tend to wear out (vanes) quickly and must have costlymachining due to close tolerances. They do move high volumes of air. Therotary compressor is quiet, has low vibration and is not designed forhigh pressure when oil-less they and wear out quickly but have a smoothnon-pulsating output flow.

Compressors in many industrial environments would benefit from betterefficiencies in allowing for multiple pistons driven by common shaftswith less duplication in parts and therefore lighter weight assemblies.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, a compressor for moving a gas from an inlet to anoutlet provides a pressure differential between the inlet and the outletdue to respective pistons moving in and out of a plurality of pistonchambers. A rotating shaft extends in a first direction through agrooved end plate extending across the compressor in a second directionsubstantially perpendicular to the rotating shaft, and the rotatingshaft is connected to either the grooved end plate or the piston rod.The grooved end plate defines a substantially circular groove positionedoff center with respect to the shaft, and a piston rod extends throughthe compressor substantially perpendicular to the rotating shaft. Thepiston rod slides back and forth relative to the rotating shaft suchthat the respective pistons are alternately closer to and farther fromthe rotating shaft. The compressor further includes a bearing extendingfrom the piston rod and fitting within the groove in the first end platesuch that when the rotational motion of the shaft rotates either thepiston rod or the first end plate, the bearing traverses the groove inthe first end plate. Each position of the bearing within the groovedetermines a corresponding position of the piston rod relative to therotating shaft.

In a different embodiment, a compressor moves a gas from an inlet to anoutlet and provides a pressure differential between the inlet and theoutlet. The compressor includes a rotating shaft extending in a firstdirection through the compressor and a piston rod extending through thecompressor in a second direction substantially perpendicular to therotating shaft. The piston rod connects respective pistons at oppositeends of the piston rod, and the piston rod slides back and forthrelative to the rotating shaft such that said respective pistons arealternately closer to and farther from said rotating shaft. A bearingextends from the piston rod, and a grooved end plate extendssubstantially parallel to the piston rod. The grooved plate defines agroove that receives the bearing therein, wherein the groove within thegrooved end plate is off-center with respect to the shaft. The bearingtraverses the groove when the rotational motion of the shaft rotateseither the piston rod or the grooved end plate. Each position of thebearing within the groove determines a corresponding position of thepiston rod relative to the rotating shaft.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a front plan view of a prior art wobble piston compressor.

FIG. 2 is a front plan view of a prior art rotary vane compressor.

FIG. 3A is a plan cross sectional view of a compressor as describedherein.

FIG. 3B is a plan view of the compressor of FIG. 3A.

FIG. 3C is a side view of the compressor of FIG. 3A.

FIG. 4 is a side cross sectional view of the compressor shown in FIG.3C.

FIG. 5A is a perspective view of a dual piston rod compressor asdescribed herein.

FIG. 5B is a top view of the dual piston rod compressor of FIG. 5A.

FIG. 5C is a side cross sectional view of the dual piston rod compressoras viewed along the line 5C-5C of FIG. 5B.

FIG. 5D is a second side cross section view of the dual piston rodcompressor as viewed along the line 5D-5D of FIG. 5B.

FIG. 6 is an exploded view of a dual piston compressor having fourpistons as described herein.

FIG. 7 is a cross section view of a compressor as described herein andhaving a lip seal matching inlet and outlet ports.

FIG. 8 is a cross section view of a compressor as described herein andhaving a labyrinth seal matching inlet and outlet ports.

FIG. 9 is a cross section view of a compressor as described herein andhaving a check valves configured to match inlet and outlet ports.

FIG. 10A is a cross section view of a compressor as described herein andhaving inlet and outlet ports on opposite sides of an associated seal.

FIG. 10B is a cross section view of a compressor as described herein andhaving inlet and outlet ports on the bottom side of an associated seal.

DETAILED DESCRIPTION

FIGS. 3A to 3C included herein illustrate a compressor that is usefulfor compressing air, specific gases (e.g., oxygen compression), or evenfluids. The term “fluids” is used in its broadest sense to encompass anymatter that flows and can be subject to pressure, whether in gaseous orliquid form. In that regard, the compressor may be referred to as afluid compressor, an oxygen compressor, or an air compressor because thenature of the medium being compressed does not change the structure ofthe invention claimed herein.

The compressor of FIG. 3A shows an overview of one embodiment of theinvention. The compressor (50) incorporates a base end plate (70)extending across the compressor (50) and allowing a rotating shaft (60)to extend there through. The rotating shaft (50) is connected to a powersource delivering rotational energy in standard mechanical embodimentsthat are not shown in the art (e.g., motors driving the rotating shaft).The rotating shaft (60) can rotate in either a forward or reversedirection, depending on the desired orientation for an inlet and outletof compressed gases or fluids.

In one embodiment, the rotating shaft (60) extends through thecompressor (50) in a vertical orientation when the base end plate (70)crosses the compressor (50) in a substantially horizontal configuration.The rotating shaft (60) extends from the base end plate (70) through thecompressor body (52) and terminates at or near a grooved end plate (72).The grooved end plate (72) is characterized in part by defining a groove(58), which in one embodiment is a substantially circular groove (58).The circular nature of the groove (58), however, is not limiting of theinvention, and the groove (58) may take any shape that affords theconvenience of providing a track for guiding pistons within thecompressor. In one embodiment that does not limit the invention, thegroove (58) may include elliptical or oblong shapes or have portions ofthe groove (58) that define straight segments instead of arcuate paths.

The groove (58) in the grooved end plate (72) is configured to receive abearing (65) that adjusts the position of associated pistons (55A, 55B)by traversing the stationary groove (58). In the alternative, the groove(58) may traverse a stationary bearing (65). In other words, therotating shaft (60) may be attached to the grooved end plate (72) andimpart rotational energy to the grooved end plate (72) so that thegroove (58) moves about a bearing (65).

In one non-limiting embodiment of the compressor (50), the bearing (65)is attached to a piston rod (75) that terminates on opposite ends withrespective pistons (55A, 55B). The pistons (55A, 55B) move back andforth within piston chambers (54A, 54B). In this regard, the compressor(50) accommodates a sliding lateral movement by the piston rod (75), andthe position is determined by the forces acting upon the bearing (65)attached to the piston rod (75). In one embodiment, the piston rod (75)is a single, continuous piston rod with no breaks or interruptions alongthe length between the pistons (55A, 55B). The piston chambers (54A,54B) are sized to provide appropriate space for the pistons to move backand forth.

In the embodiment of FIG. 3A, the piston rod (75) defines an opening(78) (also shown in FIGS. 5A and 5B) through which the rotating shaft(60) extends; the rotating shaft (60) continues through the piston rod(75) to the grooved end plate (72). Depending upon the embodiment athand, the rotating shaft (60) may be physically connected to either thepiston rod (75) or the grooved end plate (72) and impart rotationalmotion to either. The rotational motion from the rotating shaft (60),applied to the piston rod (75), allows the bearing (65) to traverse thegroove (58) in the grooved end plate (72). When the rotational motionfrom the rotating shaft (60) is applied to grooved end plate (72), thegrooved end plate actually turns so that the groove (58) actuallytraverses the bearing (65). Whether the rotating shaft (60) attaches andimparts rotational motion to the piston rod (75) or the grooved endplate (72), the result is that the groove (58) determines the rotationalforces on the bearing (65) that in turn applies forces to the piston rod(75).

As shown by the arrows of FIG. 3A, when the rotating shaft (60) isconnected to the grooved end plate (72) and thereby turns the groovedend plate along with the groove (58), the bearing (65) attached to thepiston rod (75) determines whether the piston rod (75) slides laterallyback and forth. The position of the bearing (65) within the groove (58)will determine the extent to which the piston rod (72) slides along theopening (78) defined within the piston rod (72).

As an example, FIG. 3A shows the grooved end plate (72) turning with thebearing (65) within the “eccentric” or “off-center” groove (58). In thisregard, the term “eccentric” or “off-center” means that the center ofthe groove (58) is not identical with the vertical axis of thecompressor or the rotating shaft (60). The eccentric groove (58) allowsthe bearing to adjust the lateral position of the piston rod (75)because as the bearing (65) traverses the groove (58), or the groove(58) slides over the bearing (65), the orientation of the groove andbearing contact pushes the associated piston rod in a lateral, orhorizontal direction. In the embodiment of FIG. 3A, when the grooved endplate (72) rotates the groove over the bearing (65), the groove pushesthe bearing and the bearing pushes the piston rod (75). The piston rodin this embodiment will slide back and forth with the pistons moving anequal amount within the piston chambers.

In a different scenario, when the rotating shaft (60) turns the pistonrod (75) so that the piston rod swings outwardly in a circular pattern,the bearing moving within the groove continuously changes the lateralposition of the pistons in relation to the rotating shaft.

In either set up, whether the piston rod rotates in a horizontal planeand slides back and forth continuously as the bearing traverses thegroove, or whether the grooved end plate rotates in a second horizontalplane so that the stationary bearing (65) pushes the piston rod back andforth, the result is that the pistons (55A, 55B) are alternatelypositioned closer to and farther from the rotating shaft. As a pistonmoves closer to the rotating shaft and out of an associated pistonchamber, a vacuum is created in the piston chamber. As the piston movesfarther away from the rotating shaft and deeper into the piston chamber,gases or fluids in the chamber are compressed by the piston. FIG. 3Ashows a network of ports (62A-62D) connecting the piston chambers withappropriate inlets (62D) and outlets (62A) within the device. Properlyoriented valves (63A, 63B) may be utilized to ensure proper input andoutput flow from the piston chambers (54A, 54B), respectively. Thenetwork of ports may be bored into the body of the compressor (50) byknown means. The porting (62A-62D) is normally designed into thestationary portion of the compressor (50) so that outside instruments orattachments can utilize the compressed fluid on the outlet side.

FIGS. 3A-3C also show a lip seal (80) surrounding the porting section(62B, 62C) of the compressor (50). In one embodiment, the seal for theporting is a lip seal (80). FIGS. 3B and 3C show the differentperspectives of the compressor (50) along with the output ports for theseal (80). The seal body (84) is shown even more clearly in FIG. 4,which is a side cross section of the embodiment of FIG. 3. In thedrawing of FIG. 4, the seal body (84) surrounds a portion of thecompressor (50) proximate the base end plate (70) and surrounds aportion of the rotating shaft (60) between the base end plate (70) andthe piston rod (75). The ports (62A-62D) defined within the compressorbody (52) match the corresponding ports (82A, 82B) of the seal.

The embodiment of FIG. 3 may also be expanded to the embodiment of FIGS.5A-5D, showing that the compressor may incorporate more than one pistonrod and more than one set of pistons within the same device. Thecompressor (51) includes dual piston rods (75A, 75B) which operate uponthe same principles discussed above in regard to FIG. 3. Each piston rod(75A, 75B) includes a respective bearing (65A, 65B) that engages asingle groove (58) within a grooved end plate (72). Each piston rod, ofcourse, terminates in opposite pistons with respective piston chambers.As shown in FIG. 5A, the rotating shaft (60) turns the dual piston rods(75A, 75B) simultaneously so that each traverses the same groove (58).In the embodiment of FIG. 5, the piston rods (75A, 75B) are positionedsuch that on is on top of the other, but this embodiment is forillustration purposes only. As shown in the Figures, the piston chambers(54A-54D) are all at equal heights, so the pistons terminating a toppiston rod (75B) would be adjusted in height to fit an appropriatepiston chamber that is level will all other piston chambers.

FIG. 6 shows one example of an exploded view of a compressor accordingto FIG. 5 utilizing dual piston rods (75A, 75B). FIG. 6 illustrates thatthe orientation of the components of the compressor may be adjusted forthe use at hand, and in the embodiment of FIG. 6, the rotating shaft(60) fits through the eccentrically grooved end plate (72) passesthrough washers (91, 96A, 96B) as well as housing gasket (94). The headcomponent (99) provides appropriate ports and seals for arranging thedual piston rods (75A, 75B) so that the pistons (55A-55D) move back andforth within appropriate piston chambers (54A-54D).

FIGS. 7-10 illustrate methods of developing port networks within thebody of a compressor and providing an appropriate seal therein. Theporting may be either individualized with each piston chamber having adiscrete set of input and output ports, or the porting may be combinableso that a given set of ports serves more than one piston chamber. FIG. 7illustrates that the compressor body (52) extends around the rotatingshaft (60) and includes appropriate input and output ports (82A, 82B).The lip seal (80) includes proper lip seal elements (86A-86F) to ensurethat peripheral equipment has access to the porting network with no lossof efficiency in terms of flow rate or pressure differential.

FIG. 8 illustrates a labyrinth seal (105A, 105B) as another option forsealing the ports (62A, 62B). The labyrinth seal (105) may include dualportions (105A, 105B) that fit together to allow the input and outputports to maintain maximum efficiency in operation.

FIG. 9 shows that the ports may be managed by appropriate check valves,while FIGS. 10A and 10B illustrate numerous locations for the ports onboth the compressor body and the associated seal.

The materials used in forming the compressor described above, mayinclude Teflon® or Rulon® piston seals or other slippery, low frictionpiston seals which are self-entering and floating and maintain thealignment of the piston. The seals may be dual facing. The body of thecompressor, the piston rods, the pistons, and the plates within thecompressor may be made of durable materials, such as low carbon steels,aluminum, and even polymeric synthetic materials. The appropriatematerials can be selected for both the compressor and the associatedseals to minimize or at least control thermal expansion of thecomponents during use.

While specific embodiments of the invention have are illustrated anddescribed herein, it is realized that numerous modifications and changeswill occur to those skilled in the art. It is therefore to be understoodthat the appended claims are intended to cover all such modificationsand changes that fall within the true spirit and scope of the invention.

What is claimed is:
 1. A compressor for moving a gas from an inlet to anoutlet and providing a pressure differential between the inlet and theoutlet due to respective pistons moving in and out of a plurality ofpiston chambers, wherein a rotating shaft extends in a first directionthrough a grooved end plate extending across the compressor in a seconddirection substantially perpendicular to the rotating shaft, wherein therotating shaft is connected to either the grooved end plate or thepiston rod, wherein the grooved end plate defines a substantiallycircular groove positioned off center with respect to the shaft, andwherein a piston rod extends through the compressor substantiallyperpendicular to the rotating shaft, the piston rod sliding back andforth relative to the rotating shaft such that the respective pistonsare alternately closer to and farther from the rotating shaft, thecompressor comprising: a bearing extending from the piston rod andfitting within the groove in the first end plate such that when therotational motion of the shaft rotates either the piston rod or thefirst end plate, the bearing traverses the groove in the first endplate, wherein each position of the bearing within the groove determinesa corresponding position of the piston rod relative to the rotatingshaft.
 2. A compressor according to claim 1, wherein the piston roddefines an opening through which the rotating shaft extends, wherein therotating shaft engages the piston rod and imparts rotational motion tothe piston rod.
 3. A compressor according to claim 2, wherein therotational motion rotates the piston rod along a path that is parallelto the grooved end plate such that the respective pistons advance andretract within respective piston chambers as the piston rod slides backand forth about the rotating shaft.
 4. A compressor according to claim2, wherein the rotating shaft rotates the piston rod within a plane thatis perpendicular to the rotating shaft, and said bearing traverses thegroove as the piston rod rotates, wherein the piston rod slides aboutthe rotating shaft within the opening in the piston rod as the positionof the bearing within the groove changes.
 5. A compressor according toclaim 1, wherein the rotating shaft is connected to the grooved endplate and imparts rotational motion to the grooved end plate such thatthe groove in the grooved end plate traverses the bearing on the pistonrod to impart lateral motion on the piston rod and slide the respectivepistons in and out of the piston chambers.
 6. A compressor for moving agas from an inlet to an outlet and providing a pressure differentialbetween the inlet and the outlet, the compressor comprising: a rotatingshaft extending in a first direction through the compressor; a pistonrod extending through the compressor in a second direction substantiallyperpendicular to the rotating shaft and connecting respective pistons atopposite ends of said piston rod, wherein said piston rod slides backand forth relative to said rotating shaft such that said respectivepistons are alternately closer to and farther from said rotating shaft;a bearing extending from said piston rod; a grooved end plate extendingsubstantially parallel to said piston rod and defining a groove thatreceives said bearing therein, wherein the groove within said groovedend plate is off-center with respect to said shaft; wherein said bearingtraverses the groove when the rotational motion of the shaft rotateseither said piston rod or said grooved end plate; and wherein eachposition of the bearing within the groove determines a correspondingposition of the piston rod relative to the rotating shaft.
 7. Acompressor according to claim 6, wherein said piston rod defines anopening through which said rotating shaft extends, and wherein theopening defines a length of travel for the piston rod to slide back andforth about said rotating shaft as the bearing traverses the groove inthe grooved end plate.
 8. A compressor according to claim 7, wherein therotating shaft is connected to the grooved end plate and impartsrotational motion to the grooved end plate such that the groove in thegrooved end plate traverses the bearing on the piston rod to impartlateral motion on the piston rod and slide the respective pistons backand forth about the rotating shaft.
 9. A compressor according to claim7, wherein the rotating shaft is connected to the grooved end plate andimparts rotational motion to the grooved end plate such that the groovein the grooved end plate traverses the bearing on the piston rod toimpart lateral motion on the piston rod and slide the respective pistonsback and forth about the rotating shaft.
 10. A compressor according toclaim 6, further comprising piston chambers in which said respectivepistons slide to alternately create a vacuum and a higher pressurevolume for gas within the piston chambers.
 11. A compressor according toclaim 6, further comprising a network of ports within the compressor,said network of ports connecting the inlet and the outlet.
 12. Acompressor according to claim 11, further comprising at least one sealcontrolling the entry and exit of the gas into and out of thecompressor.
 13. A compressor according to claim 12, wherein said sealextends around said compressor and parallel to said rotating shaft. 14.A compressor according to claim 13, wherein said seal comprises sealoutlets extending substantially perpendicularly to said rotating shaftand extending from a side edge of said seal.
 15. A compressor accordingto claim 13, wherein said seal comprises seal outlets extendingsubstantially parallel to said rotating shaft and extending from abottom edge of said seal.
 16. A compressor according to claim 13,wherein said seal is a lip seal.
 17. A compressor according to claim 13,wherein said seal is a labyrinth seal.
 18. A compressor according toclaim 6, further comprising a compressor body encompassing pistonchambers through which said pistons move as said piston rod slideslaterally across said rotating shaft.
 19. A compressor according toclaim 18, wherein said piston chambers alternately create a vacuum and aregion of increased pressure as said pistons slide into and out saidpiston chambers.
 20. A compressor according to claim 19, wherein saidpiston chambers are connected to ports defined within the compressorbody, said ports defining entry and exit points for gas in thecompressor.
 21. A compressor for moving a gas from an inlet to an outletand providing a pressure differential between the inlet and the outlet,the compressor comprising: a rotating shaft extending in a firstdirection through the compressor; a first piston rod extending throughthe compressor in a second direction substantially perpendicular to therotating shaft and connecting respective pistons at opposite ends ofsaid piston rod, wherein said piston rod slides back and forth relativeto said rotating shaft such that said respective pistons are alternatelycloser to and farther from said rotating shaft; a second piston rodextending through the compressor in a third direction substantiallyperpendicular to the rotating shaft the first piston rod, said secondpiston rod connecting a second pair of pistons at opposite ends of saidsecond piston rod, wherein said second piston rod slides back and forthrelative to said rotating shaft such that said second pair of pistonsare alternately closer to and farther from said rotating shaft; a firstbearing extending from said first piston rod; a second bearing extendingfrom said second piston rod; a grooved end plate extending substantiallyparallel to said first and second piston rods and defining a groove thatreceives said first and second bearings therein, wherein the groovewithin said grooved end plate is off-center with respect to said shaft;wherein said first and second bearings traverse the groove when therotational motion of the shaft rotates either said first and secondpiston rods or said grooved end plate; and wherein each position of eachrespective first and second bearing within the groove determines acorresponding position of the respective first and second piston rodrelative to the rotating shaft.
 22. A compressor according to claim 21,wherein said second piston rod is positioned atop said first piston rod.23. A compressor according to claim 22, wherein both of said piston rodsdefine respective openings through which said rotating shaft extends.24. A compressor according to claim 23, wherein said piston rods slideback and forth about the rotating shaft via the respective openings. 25.A compressor according to claim 24, further comprising respective pairsof piston chambers in which the respective pairs of pistons fit withinthe compressor.